/*
 * EAP peer method: EAP-FAST (RFC 4851)
 * Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "eap_i.h"
#include "eap_tls_common.h"
#include "eap_config.h"
#include "tls.h"
#include "eap_common/eap_tlv_common.h"
#include "sha1.h"
#include "eap_fast_pac.h"

#ifdef EAP_FAST_DYNAMIC
#include "eap_fast_pac.c"
#endif /* EAP_FAST_DYNAMIC */

/* TODO:
 * - test session resumption and enable it if it interoperates
 * - password change (pending mschapv2 packet; replay decrypted packet)
 */


static void eap_fast_deinit(struct eap_sm *sm, void *priv);


struct eap_fast_data {
        struct eap_ssl_data ssl;

        int fast_version;

        const struct eap_method *phase2_method;
        void *phase2_priv;
        int phase2_success;

        struct eap_method_type phase2_type;
        struct eap_method_type *phase2_types;
        size_t num_phase2_types;
        int resuming; /* starting a resumed session */
        struct eap_fast_key_block_provisioning *key_block_p;
#define EAP_FAST_PROV_UNAUTH 1
#define EAP_FAST_PROV_AUTH 2
        int provisioning_allowed; /* Allowed PAC provisioning modes */
        int provisioning; /* doing PAC provisioning (not the normal auth) */
        int anon_provisioning; /* doing anonymous (unauthenticated)
                                * provisioning */
        int session_ticket_used;

        u8 key_data[EAP_FAST_KEY_LEN];
        u8 emsk[EAP_EMSK_LEN];
        int success;

        struct eap_fast_pac *pac;
        struct eap_fast_pac *current_pac;
        size_t max_pac_list_len;
        int use_pac_binary_format;

        u8 simck[EAP_FAST_SIMCK_LEN];
        int simck_idx;

        struct wpabuf *pending_phase2_req;
};


static int eap_fast_session_ticket_cb(void *ctx, const u8 *ticket, size_t len,
                                      const u8 *client_random,
                                      const u8 *server_random,
                                      u8 *master_secret)
{
        struct eap_fast_data *data = ctx;

        wpa_printf(MSG_DEBUG, "EAP-FAST: SessionTicket callback");

        if (client_random == NULL || server_random == NULL ||
            master_secret == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: SessionTicket failed - fall "
                           "back to full TLS handshake");
                data->session_ticket_used = 0;
                if (data->provisioning_allowed) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Try to provision a "
                                   "new PAC-Key");
                        data->provisioning = 1;
                        data->current_pac = NULL;
                }
                return 0;
        }

        wpa_hexdump(MSG_DEBUG, "EAP-FAST: SessionTicket", ticket, len);

        if (data->current_pac == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: No PAC-Key available for "
                           "using SessionTicket");
                data->session_ticket_used = 0;
                return 0;
        }

        eap_fast_derive_master_secret(data->current_pac->pac_key,
                                      server_random, client_random,
                                      master_secret);

        data->session_ticket_used = 1;

        return 1;
}


static int eap_fast_parse_phase1(struct eap_fast_data *data,
                                 const char *phase1)
{
        const char *pos;

        pos = os_strstr(phase1, "fast_provisioning=");
        if (pos) {
                data->provisioning_allowed = atoi(pos + 18);
                wpa_printf(MSG_DEBUG, "EAP-FAST: Automatic PAC provisioning "
                           "mode: %d", data->provisioning_allowed);
        }

        pos = os_strstr(phase1, "fast_max_pac_list_len=");
        if (pos) {
                data->max_pac_list_len = atoi(pos + 22);
                if (data->max_pac_list_len == 0)
                        data->max_pac_list_len = 1;
                wpa_printf(MSG_DEBUG, "EAP-FAST: Maximum PAC list length: %lu",
                           (unsigned long) data->max_pac_list_len);
        }

        pos = os_strstr(phase1, "fast_pac_format=binary");
        if (pos) {
                data->use_pac_binary_format = 1;
                wpa_printf(MSG_DEBUG, "EAP-FAST: Using binary format for PAC "
                           "list");
        }

        return 0;
}


static void * eap_fast_init(struct eap_sm *sm)
{
        struct eap_fast_data *data;
        struct eap_peer_config *config = eap_get_config(sm);

        data = os_zalloc(sizeof(*data));
        if (data == NULL)
                return NULL;
        data->fast_version = EAP_FAST_VERSION;
        data->max_pac_list_len = 10;

        if (config && config->phase1 &&
            eap_fast_parse_phase1(data, config->phase1) < 0) {
                eap_fast_deinit(sm, data);
                return NULL;
        }

        if (eap_peer_select_phase2_methods(config, "auth=",
                                           &data->phase2_types,
                                           &data->num_phase2_types) < 0) {
                eap_fast_deinit(sm, data);
                return NULL;
        }

        data->phase2_type.vendor = EAP_VENDOR_IETF;
        data->phase2_type.method = EAP_TYPE_NONE;

        if (eap_peer_tls_ssl_init(sm, &data->ssl, config)) {
                wpa_printf(MSG_INFO, "EAP-FAST: Failed to initialize SSL.");
                eap_fast_deinit(sm, data);
                return NULL;
        }

        if (tls_connection_set_session_ticket_cb(sm->ssl_ctx, data->ssl.conn,
                                                 eap_fast_session_ticket_cb,
                                                 data) < 0) {
                wpa_printf(MSG_INFO, "EAP-FAST: Failed to set SessionTicket "
                           "callback");
                eap_fast_deinit(sm, data);
                return NULL;
        }

        /*
         * The local RADIUS server in a Cisco AP does not seem to like empty
         * fragments before data, so disable that workaround for CBC.
         * TODO: consider making this configurable
         */
        if (tls_connection_enable_workaround(sm->ssl_ctx, data->ssl.conn)) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to enable TLS "
                           "workarounds");
        }

        if (data->use_pac_binary_format &&
            eap_fast_load_pac_bin(sm, &data->pac, config->pac_file) < 0) {
                eap_fast_deinit(sm, data);
                return NULL;
        }

        if (!data->use_pac_binary_format &&
            eap_fast_load_pac(sm, &data->pac, config->pac_file) < 0) {
                eap_fast_deinit(sm, data);
                return NULL;
        }
        eap_fast_pac_list_truncate(data->pac, data->max_pac_list_len);

        if (data->pac == NULL && !data->provisioning_allowed) {
                wpa_printf(MSG_INFO, "EAP-FAST: No PAC configured and "
                           "provisioning disabled");
                eap_fast_deinit(sm, data);
                return NULL;
        }

        return data;
}


static void eap_fast_deinit(struct eap_sm *sm, void *priv)
{
        struct eap_fast_data *data = priv;
        struct eap_fast_pac *pac, *prev;

        if (data == NULL)
                return;
        if (data->phase2_priv && data->phase2_method)
                data->phase2_method->deinit(sm, data->phase2_priv);
        os_free(data->phase2_types);
        os_free(data->key_block_p);
        eap_peer_tls_ssl_deinit(sm, &data->ssl);

        pac = data->pac;
        prev = NULL;
        while (pac) {
                prev = pac;
                pac = pac->next;
                eap_fast_free_pac(prev);
        }
        wpabuf_free(data->pending_phase2_req);
        os_free(data);
}


static int eap_fast_derive_msk(struct eap_fast_data *data)
{
        eap_fast_derive_eap_msk(data->simck, data->key_data);
        eap_fast_derive_eap_emsk(data->simck, data->emsk);
        data->success = 1;
        return 0;
}


static void eap_fast_derive_key_auth(struct eap_sm *sm,
                                     struct eap_fast_data *data)
{
        u8 *sks;

        /* RFC 4851, Section 5.1:
         * Extra key material after TLS key_block: session_key_seed[40]
         */

        sks = eap_fast_derive_key(sm->ssl_ctx, data->ssl.conn, "key expansion",
                                  EAP_FAST_SKS_LEN);
        if (sks == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to derive "
                           "session_key_seed");
                return;
        }

        /*
         * RFC 4851, Section 5.2:
         * S-IMCK[0] = session_key_seed
         */
        wpa_hexdump_key(MSG_DEBUG,
                        "EAP-FAST: session_key_seed (SKS = S-IMCK[0])",
                        sks, EAP_FAST_SKS_LEN);
        data->simck_idx = 0;
        os_memcpy(data->simck, sks, EAP_FAST_SIMCK_LEN);
        os_free(sks);
}


static void eap_fast_derive_key_provisioning(struct eap_sm *sm,
                                             struct eap_fast_data *data)
{
        os_free(data->key_block_p);
        data->key_block_p = (struct eap_fast_key_block_provisioning *)
                eap_fast_derive_key(sm->ssl_ctx, data->ssl.conn,
                                    "key expansion",
                                    sizeof(*data->key_block_p));
        if (data->key_block_p == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to derive key block");
                return;
        }
        /*
         * RFC 4851, Section 5.2:
         * S-IMCK[0] = session_key_seed
         */
        wpa_hexdump_key(MSG_DEBUG,
                        "EAP-FAST: session_key_seed (SKS = S-IMCK[0])",
                        data->key_block_p->session_key_seed,
                        sizeof(data->key_block_p->session_key_seed));
        data->simck_idx = 0;
        os_memcpy(data->simck, data->key_block_p->session_key_seed,
                  EAP_FAST_SIMCK_LEN);
        wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: server_challenge",
                        data->key_block_p->server_challenge,
                        sizeof(data->key_block_p->server_challenge));
        wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: client_challenge",
                        data->key_block_p->client_challenge,
                        sizeof(data->key_block_p->client_challenge));
}


static void eap_fast_derive_keys(struct eap_sm *sm, struct eap_fast_data *data)
{
        if (data->anon_provisioning)
                eap_fast_derive_key_provisioning(sm, data);
        else
                eap_fast_derive_key_auth(sm, data);
}


static int eap_fast_init_phase2_method(struct eap_sm *sm,
                                       struct eap_fast_data *data)
{
        data->phase2_method =
                eap_peer_get_eap_method(data->phase2_type.vendor,
                                        data->phase2_type.method);
        if (data->phase2_method == NULL)
                return -1;

        if (data->key_block_p) {
                sm->auth_challenge = data->key_block_p->server_challenge;
                sm->peer_challenge = data->key_block_p->client_challenge;
        }
        sm->init_phase2 = 1;
        data->phase2_priv = data->phase2_method->init(sm);
        sm->init_phase2 = 0;
        sm->auth_challenge = NULL;
        sm->peer_challenge = NULL;

        return data->phase2_priv == NULL ? -1 : 0;
}


static int eap_fast_select_phase2_method(struct eap_fast_data *data, u8 type)
{
        size_t i;

        /* TODO: TNC with anonymous provisioning; need to require both
         * completed MSCHAPv2 and TNC */

        if (data->anon_provisioning && type != EAP_TYPE_MSCHAPV2) {
                wpa_printf(MSG_INFO, "EAP-FAST: Only EAP-MSCHAPv2 is allowed "
                           "during unauthenticated provisioning; reject phase2"
                           " type %d", type);
                return -1;
        }

#ifdef EAP_TNC
        if (type == EAP_TYPE_TNC) {
                data->phase2_type.vendor = EAP_VENDOR_IETF;
                data->phase2_type.method = EAP_TYPE_TNC;
                wpa_printf(MSG_DEBUG, "EAP-FAST: Selected Phase 2 EAP "
                           "vendor %d method %d for TNC",
                           data->phase2_type.vendor,
                           data->phase2_type.method);
                return 0;
        }
#endif /* EAP_TNC */

        for (i = 0; i < data->num_phase2_types; i++) {
                if (data->phase2_types[i].vendor != EAP_VENDOR_IETF ||
                    data->phase2_types[i].method != type)
                        continue;

                data->phase2_type.vendor = data->phase2_types[i].vendor;
                data->phase2_type.method = data->phase2_types[i].method;
                wpa_printf(MSG_DEBUG, "EAP-FAST: Selected Phase 2 EAP "
                           "vendor %d method %d",
                           data->phase2_type.vendor,
                           data->phase2_type.method);
                break;
        }

        if (type != data->phase2_type.method || type == EAP_TYPE_NONE)
                return -1;

        return 0;
}


static int eap_fast_phase2_request(struct eap_sm *sm,
                                   struct eap_fast_data *data,
                                   struct eap_method_ret *ret,
                                   struct eap_hdr *hdr,
                                   struct wpabuf **resp)
{
        size_t len = be_to_host16(hdr->length);
        u8 *pos;
        struct eap_method_ret iret;
        struct eap_peer_config *config = eap_get_config(sm);
        struct wpabuf msg;

        if (len <= sizeof(struct eap_hdr)) {
                wpa_printf(MSG_INFO, "EAP-FAST: too short "
                           "Phase 2 request (len=%lu)", (unsigned long) len);
                return -1;
        }
        pos = (u8 *) (hdr + 1);
        wpa_printf(MSG_DEBUG, "EAP-FAST: Phase 2 Request: type=%d", *pos);
        if (*pos == EAP_TYPE_IDENTITY) {
                *resp = eap_sm_buildIdentity(sm, hdr->identifier, 1);
                return 0;
        }

        if (data->phase2_priv && data->phase2_method &&
            *pos != data->phase2_type.method) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Phase 2 EAP sequence - "
                           "deinitialize previous method");
                data->phase2_method->deinit(sm, data->phase2_priv);
                data->phase2_method = NULL;
                data->phase2_priv = NULL;
                data->phase2_type.vendor = EAP_VENDOR_IETF;
                data->phase2_type.method = EAP_TYPE_NONE;
        }

        if (data->phase2_type.vendor == EAP_VENDOR_IETF &&
            data->phase2_type.method == EAP_TYPE_NONE &&
            eap_fast_select_phase2_method(data, *pos) < 0) {
                if (eap_peer_tls_phase2_nak(data->phase2_types,
                                            data->num_phase2_types,
                                            hdr, resp))
                        return -1;
                return 0;
        }

        if (data->phase2_priv == NULL &&
            eap_fast_init_phase2_method(sm, data) < 0) {
                wpa_printf(MSG_INFO, "EAP-FAST: Failed to initialize "
                           "Phase 2 EAP method %d", *pos);
                ret->methodState = METHOD_DONE;
                ret->decision = DECISION_FAIL;
                return -1;
        }

        os_memset(&iret, 0, sizeof(iret));
        wpabuf_set(&msg, hdr, len);
        *resp = data->phase2_method->process(sm, data->phase2_priv, &iret,
                                             &msg);
        if (*resp == NULL ||
            (iret.methodState == METHOD_DONE &&
             iret.decision == DECISION_FAIL)) {
                ret->methodState = METHOD_DONE;
                ret->decision = DECISION_FAIL;
        } else if ((iret.methodState == METHOD_DONE ||
                    iret.methodState == METHOD_MAY_CONT) &&
                   (iret.decision == DECISION_UNCOND_SUCC ||
                    iret.decision == DECISION_COND_SUCC)) {
                data->phase2_success = 1;
        }

        if (*resp == NULL && config &&
            (config->pending_req_identity || config->pending_req_password ||
             config->pending_req_otp || config->pending_req_new_password)) {
                wpabuf_free(data->pending_phase2_req);
                data->pending_phase2_req = wpabuf_alloc_copy(hdr, len);
        } else if (*resp == NULL)
                return -1;

        return 0;
}


static struct wpabuf * eap_fast_tlv_nak(int vendor_id, int tlv_type)
{
        struct wpabuf *buf;
        struct eap_tlv_nak_tlv *nak;
        buf = wpabuf_alloc(sizeof(*nak));
        if (buf == NULL)
                return NULL;
        nak = wpabuf_put(buf, sizeof(*nak));
        nak->tlv_type = host_to_be16(EAP_TLV_TYPE_MANDATORY | EAP_TLV_NAK_TLV);
        nak->length = host_to_be16(6);
        nak->vendor_id = host_to_be32(vendor_id);
        nak->nak_type = host_to_be16(tlv_type);
        return buf;
}


static struct wpabuf * eap_fast_tlv_result(int status, int intermediate)
{
        struct wpabuf *buf;
        struct eap_tlv_intermediate_result_tlv *result;
        buf = wpabuf_alloc(sizeof(*result));
        if (buf == NULL)
                return NULL;
        wpa_printf(MSG_DEBUG, "EAP-FAST: Add %sResult TLV(status=%d)",
                   intermediate ? "Intermediate " : "", status);
        result = wpabuf_put(buf, sizeof(*result));
        result->tlv_type = host_to_be16(EAP_TLV_TYPE_MANDATORY |
                                        (intermediate ?
                                         EAP_TLV_INTERMEDIATE_RESULT_TLV :
                                         EAP_TLV_RESULT_TLV));
        result->length = host_to_be16(2);
        result->status = host_to_be16(status);
        return buf;
}


static struct wpabuf * eap_fast_tlv_pac_ack(void)
{
        struct wpabuf *buf;
        struct eap_tlv_result_tlv *res;
        struct eap_tlv_pac_ack_tlv *ack;

        buf = wpabuf_alloc(sizeof(*res) + sizeof(*ack));
        if (buf == NULL)
                return NULL;

        wpa_printf(MSG_DEBUG, "EAP-FAST: Add PAC TLV (ack)");
        ack = wpabuf_put(buf, sizeof(*ack));
        ack->tlv_type = host_to_be16(EAP_TLV_PAC_TLV |
                                     EAP_TLV_TYPE_MANDATORY);
        ack->length = host_to_be16(sizeof(*ack) - sizeof(struct eap_tlv_hdr));
        ack->pac_type = host_to_be16(PAC_TYPE_PAC_ACKNOWLEDGEMENT);
        ack->pac_len = host_to_be16(2);
        ack->result = host_to_be16(EAP_TLV_RESULT_SUCCESS);

        return buf;
}


static struct wpabuf * eap_fast_process_eap_payload_tlv(
        struct eap_sm *sm, struct eap_fast_data *data,
        struct eap_method_ret *ret, const struct eap_hdr *req,
        u8 *eap_payload_tlv, size_t eap_payload_tlv_len)
{
        struct eap_hdr *hdr;
        struct wpabuf *resp = NULL;

        if (eap_payload_tlv_len < sizeof(*hdr)) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: too short EAP "
                           "Payload TLV (len=%lu)",
                           (unsigned long) eap_payload_tlv_len);
                return NULL;
        }

        hdr = (struct eap_hdr *) eap_payload_tlv;
        if (be_to_host16(hdr->length) > eap_payload_tlv_len) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: EAP packet overflow in "
                           "EAP Payload TLV");
                return NULL;
        }

        if (hdr->code != EAP_CODE_REQUEST) {
                wpa_printf(MSG_INFO, "EAP-FAST: Unexpected code=%d in "
                           "Phase 2 EAP header", hdr->code);
                return NULL;
        }

        if (eap_fast_phase2_request(sm, data, ret, hdr, &resp)) {
                wpa_printf(MSG_INFO, "EAP-FAST: Phase2 Request processing "
                           "failed");
                return NULL;
        }

        return eap_fast_tlv_eap_payload(resp);
}


static int eap_fast_validate_crypto_binding(
        struct eap_tlv_crypto_binding_tlv *_bind)
{
        wpa_printf(MSG_DEBUG, "EAP-FAST: Crypto-Binding TLV: Version %d "
                   "Received Version %d SubType %d",
                   _bind->version, _bind->received_version, _bind->subtype);
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: NONCE",
                    _bind->nonce, sizeof(_bind->nonce));
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Compound MAC",
                    _bind->compound_mac, sizeof(_bind->compound_mac));

        if (_bind->version != EAP_FAST_VERSION ||
            _bind->received_version != EAP_FAST_VERSION ||
            _bind->subtype != EAP_TLV_CRYPTO_BINDING_SUBTYPE_REQUEST) {
                wpa_printf(MSG_INFO, "EAP-FAST: Invalid version/subtype in "
                           "Crypto-Binding TLV: Version %d "
                           "Received Version %d SubType %d",
                           _bind->version, _bind->received_version,
                           _bind->subtype);
                return -1;
        }

        return 0;
}


static void eap_fast_write_crypto_binding(
        struct eap_tlv_crypto_binding_tlv *rbind,
        struct eap_tlv_crypto_binding_tlv *_bind, const u8 *cmk)
{
        rbind->tlv_type = host_to_be16(EAP_TLV_TYPE_MANDATORY |
                                       EAP_TLV_CRYPTO_BINDING_TLV);
        rbind->length = host_to_be16(sizeof(*rbind) -
                                     sizeof(struct eap_tlv_hdr));
        rbind->version = EAP_FAST_VERSION;
        rbind->received_version = _bind->version;
        rbind->subtype = EAP_TLV_CRYPTO_BINDING_SUBTYPE_RESPONSE;
        os_memcpy(rbind->nonce, _bind->nonce, sizeof(_bind->nonce));
        inc_byte_array(rbind->nonce, sizeof(rbind->nonce));
        hmac_sha1(cmk, EAP_FAST_CMK_LEN, (u8 *) rbind, sizeof(*rbind),
                  rbind->compound_mac);

        wpa_printf(MSG_DEBUG, "EAP-FAST: Reply Crypto-Binding TLV: Version %d "
                   "Received Version %d SubType %d",
                   rbind->version, rbind->received_version, rbind->subtype);
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: NONCE",
                    rbind->nonce, sizeof(rbind->nonce));
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Compound MAC",
                    rbind->compound_mac, sizeof(rbind->compound_mac));
}


static int eap_fast_get_phase2_key(struct eap_sm *sm,
                                   struct eap_fast_data *data,
                                   u8 *isk, size_t isk_len)
{
        u8 *key;
        size_t key_len;

        os_memset(isk, 0, isk_len);

        if (data->phase2_method == NULL || data->phase2_priv == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Phase 2 method not "
                           "available");
                return -1;
        }

        if (data->phase2_method->isKeyAvailable == NULL ||
            data->phase2_method->getKey == NULL)
                return 0;

        if (!data->phase2_method->isKeyAvailable(sm, data->phase2_priv) ||
            (key = data->phase2_method->getKey(sm, data->phase2_priv,
                                               &key_len)) == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Could not get key material "
                           "from Phase 2");
                return -1;
        }

        if (key_len > isk_len)
                key_len = isk_len;
        if (key_len == 32 &&
            data->phase2_method->vendor == EAP_VENDOR_IETF &&
            data->phase2_method->method == EAP_TYPE_MSCHAPV2) {
                /*
                 * EAP-FAST uses reverse order for MS-MPPE keys when deriving
                 * MSK from EAP-MSCHAPv2. Swap the keys here to get the correct
                 * ISK for EAP-FAST cryptobinding.
                 */
                os_memcpy(isk, key + 16, 16);
                os_memcpy(isk + 16, key, 16);
        } else
                os_memcpy(isk, key, key_len);
        os_free(key);

        return 0;
}


static int eap_fast_get_cmk(struct eap_sm *sm, struct eap_fast_data *data,
                            u8 *cmk)
{
        u8 isk[32], imck[60];

        wpa_printf(MSG_DEBUG, "EAP-FAST: Determining CMK[%d] for Compound MIC "
                   "calculation", data->simck_idx + 1);

        /*
         * RFC 4851, Section 5.2:
         * IMCK[j] = T-PRF(S-IMCK[j-1], "Inner Methods Compound Keys",
         *                 MSK[j], 60)
         * S-IMCK[j] = first 40 octets of IMCK[j]
         * CMK[j] = last 20 octets of IMCK[j]
         */

        if (eap_fast_get_phase2_key(sm, data, isk, sizeof(isk)) < 0)
                return -1;
        wpa_hexdump_key(MSG_MSGDUMP, "EAP-FAST: ISK[j]", isk, sizeof(isk));
        sha1_t_prf(data->simck, EAP_FAST_SIMCK_LEN,
                   "Inner Methods Compound Keys",
                   isk, sizeof(isk), imck, sizeof(imck));
        data->simck_idx++;
        os_memcpy(data->simck, imck, EAP_FAST_SIMCK_LEN);
        wpa_hexdump_key(MSG_MSGDUMP, "EAP-FAST: S-IMCK[j]",
                        data->simck, EAP_FAST_SIMCK_LEN);
        os_memcpy(cmk, imck + EAP_FAST_SIMCK_LEN, EAP_FAST_CMK_LEN);
        wpa_hexdump_key(MSG_MSGDUMP, "EAP-FAST: CMK[j]",
                        cmk, EAP_FAST_CMK_LEN);

        return 0;
}


static u8 * eap_fast_write_pac_request(u8 *pos, u16 pac_type)
{
        struct eap_tlv_hdr *pac;
        struct eap_tlv_request_action_tlv *act;
        struct eap_tlv_pac_type_tlv *type;

        act = (struct eap_tlv_request_action_tlv *) pos;
        act->tlv_type = host_to_be16(EAP_TLV_REQUEST_ACTION_TLV);
        act->length = host_to_be16(2);
        act->action = host_to_be16(EAP_TLV_ACTION_PROCESS_TLV);

        pac = (struct eap_tlv_hdr *) (act + 1);
        pac->tlv_type = host_to_be16(EAP_TLV_PAC_TLV);
        pac->length = host_to_be16(sizeof(*type));

        type = (struct eap_tlv_pac_type_tlv *) (pac + 1);
        type->tlv_type = host_to_be16(PAC_TYPE_PAC_TYPE);
        type->length = host_to_be16(2);
        type->pac_type = host_to_be16(pac_type);

        return (u8 *) (type + 1);
}


static struct wpabuf * eap_fast_process_crypto_binding(
        struct eap_sm *sm, struct eap_fast_data *data,
        struct eap_method_ret *ret,
        struct eap_tlv_crypto_binding_tlv *_bind, size_t bind_len)
{
        struct wpabuf *resp;
        u8 *pos;
        u8 cmk[EAP_FAST_CMK_LEN], cmac[SHA1_MAC_LEN];
        int res;
        size_t len;

        if (eap_fast_validate_crypto_binding(_bind) < 0)
                return NULL;

        if (eap_fast_get_cmk(sm, data, cmk) < 0)
                return NULL;

        /* Validate received Compound MAC */
        os_memcpy(cmac, _bind->compound_mac, sizeof(cmac));
        os_memset(_bind->compound_mac, 0, sizeof(cmac));
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Crypto-Binding TLV for Compound "
                    "MAC calculation", (u8 *) _bind, bind_len);
        hmac_sha1(cmk, EAP_FAST_CMK_LEN, (u8 *) _bind, bind_len,
                  _bind->compound_mac);
        res = os_memcmp(cmac, _bind->compound_mac, sizeof(cmac));
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Received Compound MAC",
                    cmac, sizeof(cmac));
        wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Calculated Compound MAC",
                    _bind->compound_mac, sizeof(cmac));
        if (res != 0) {
                wpa_printf(MSG_INFO, "EAP-FAST: Compound MAC did not match");
                os_memcpy(_bind->compound_mac, cmac, sizeof(cmac));
                return NULL;
        }

        /*
         * Compound MAC was valid, so authentication succeeded. Reply with
         * crypto binding to allow server to complete authentication.
         */

        len = sizeof(struct eap_tlv_crypto_binding_tlv);
        resp = wpabuf_alloc(len);
        if (resp == NULL)
                return NULL;

        if (!data->anon_provisioning && data->phase2_success &&
            eap_fast_derive_msk(data) < 0) {
                wpa_printf(MSG_INFO, "EAP-FAST: Failed to generate MSK");
                ret->methodState = METHOD_DONE;
                ret->decision = DECISION_FAIL;
                data->phase2_success = 0;
                wpabuf_free(resp);
                return NULL;
        }

        pos = wpabuf_put(resp, sizeof(struct eap_tlv_crypto_binding_tlv));
        eap_fast_write_crypto_binding((struct eap_tlv_crypto_binding_tlv *)
                                      pos, _bind, cmk);

        return resp;
}


static void eap_fast_parse_pac_tlv(struct eap_fast_pac *entry, int type,
                                   u8 *pos, size_t len, int *pac_key_found)
{
        switch (type & 0x7fff) {
        case PAC_TYPE_PAC_KEY:
                wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: PAC-Key", pos, len);
                if (len != EAP_FAST_PAC_KEY_LEN) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Invalid PAC-Key "
                                   "length %lu", (unsigned long) len);
                        break;
                }
                *pac_key_found = 1;
                os_memcpy(entry->pac_key, pos, len);
                break;
        case PAC_TYPE_PAC_OPAQUE:
                wpa_hexdump(MSG_DEBUG, "EAP-FAST: PAC-Opaque", pos, len);
                entry->pac_opaque = pos;
                entry->pac_opaque_len = len;
                break;
        case PAC_TYPE_PAC_INFO:
                wpa_hexdump(MSG_DEBUG, "EAP-FAST: PAC-Info", pos, len);
                entry->pac_info = pos;
                entry->pac_info_len = len;
                break;
        default:
                wpa_printf(MSG_DEBUG, "EAP-FAST: Ignored unknown PAC type %d",
                           type);
                break;
        }
}


static int eap_fast_process_pac_tlv(struct eap_fast_pac *entry,
                                    u8 *pac, size_t pac_len)
{
        struct pac_tlv_hdr *hdr;
        u8 *pos;
        size_t left, len;
        int type, pac_key_found = 0;

        pos = pac;
        left = pac_len;

        while (left > sizeof(*hdr)) {
                hdr = (struct pac_tlv_hdr *) pos;
                type = be_to_host16(hdr->type);
                len = be_to_host16(hdr->len);
                pos += sizeof(*hdr);
                left -= sizeof(*hdr);
                if (len > left) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: PAC TLV overrun "
                                   "(type=%d len=%lu left=%lu)",
                                   type, (unsigned long) len,
                                   (unsigned long) left);
                        return -1;
                }

                eap_fast_parse_pac_tlv(entry, type, pos, len, &pac_key_found);

                pos += len;
                left -= len;
        }

        if (!pac_key_found || !entry->pac_opaque || !entry->pac_info) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: PAC TLV does not include "
                           "all the required fields");
                return -1;
        }

        return 0;
}


static int eap_fast_parse_pac_info(struct eap_fast_pac *entry, int type,
                                   u8 *pos, size_t len)
{
        u16 pac_type;
        u32 lifetime;
        struct os_time now;

        switch (type & 0x7fff) {
        case PAC_TYPE_CRED_LIFETIME:
                if (len != 4) {
                        wpa_hexdump(MSG_DEBUG, "EAP-FAST: PAC-Info - "
                                    "Invalid CRED_LIFETIME length - ignored",
                                    pos, len);
                        return 0;
                }

                /*
                 * This is not currently saved separately in PAC files since
                 * the server can automatically initiate PAC update when
                 * needed. Anyway, the information is available from PAC-Info
                 * dump if it is needed for something in the future.
                 */
                lifetime = WPA_GET_BE32(pos);
                os_get_time(&now);
                wpa_printf(MSG_DEBUG, "EAP-FAST: PAC-Info - CRED_LIFETIME %d "
                           "(%d days)",
                           lifetime, (lifetime - (u32) now.sec) / 86400);
                break;
        case PAC_TYPE_A_ID:
                wpa_hexdump_ascii(MSG_DEBUG, "EAP-FAST: PAC-Info - A-ID",
                                  pos, len);
                entry->a_id = pos;
                entry->a_id_len = len;
                break;
        case PAC_TYPE_I_ID:
                wpa_hexdump_ascii(MSG_DEBUG, "EAP-FAST: PAC-Info - I-ID",
                                  pos, len);
                entry->i_id = pos;
                entry->i_id_len = len;
                break;
        case PAC_TYPE_A_ID_INFO:
                wpa_hexdump_ascii(MSG_DEBUG, "EAP-FAST: PAC-Info - A-ID-Info",
                                  pos, len);
                entry->a_id_info = pos;
                entry->a_id_info_len = len;
                break;
        case PAC_TYPE_PAC_TYPE:
                /* RFC 5422, Section 4.2.6 - PAC-Type TLV */
                if (len != 2) {
                        wpa_printf(MSG_INFO, "EAP-FAST: Invalid PAC-Type "
                                   "length %lu (expected 2)",
                                   (unsigned long) len);
                        wpa_hexdump_ascii(MSG_DEBUG,
                                          "EAP-FAST: PAC-Info - PAC-Type",
                                          pos, len);
                        return -1;
                }
                pac_type = WPA_GET_BE16(pos);
                if (pac_type != PAC_TYPE_TUNNEL_PAC &&
                    pac_type != PAC_TYPE_USER_AUTHORIZATION &&
                    pac_type != PAC_TYPE_MACHINE_AUTHENTICATION) {
                        wpa_printf(MSG_INFO, "EAP-FAST: Unsupported PAC Type "
                                   "%d", pac_type);
                        return -1;
                }

                wpa_printf(MSG_DEBUG, "EAP-FAST: PAC-Info - PAC-Type %d",
                           pac_type);
                entry->pac_type = pac_type;
                break;
        default:
                wpa_printf(MSG_DEBUG, "EAP-FAST: Ignored unknown PAC-Info "
                           "type %d", type);
                break;
        }

        return 0;
}


static int eap_fast_process_pac_info(struct eap_fast_pac *entry)
{
        struct pac_tlv_hdr *hdr;
        u8 *pos;
        size_t left, len;
        int type;

        /* RFC 5422, Section 4.2.4 */

        /* PAC-Type defaults to Tunnel PAC (Type 1) */
        entry->pac_type = PAC_TYPE_TUNNEL_PAC;

        pos = entry->pac_info;
        left = entry->pac_info_len;
        while (left > sizeof(*hdr)) {
                hdr = (struct pac_tlv_hdr *) pos;
                type = be_to_host16(hdr->type);
                len = be_to_host16(hdr->len);
                pos += sizeof(*hdr);
                left -= sizeof(*hdr);
                if (len > left) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: PAC-Info overrun "
                                   "(type=%d len=%lu left=%lu)",
                                   type, (unsigned long) len,
                                   (unsigned long) left);
                        return -1;
                }

                if (eap_fast_parse_pac_info(entry, type, pos, len) < 0)
                        return -1;

                pos += len;
                left -= len;
        }

        if (entry->a_id == NULL || entry->a_id_info == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: PAC-Info does not include "
                           "all the required fields");
                return -1;
        }

        return 0;
}


static struct wpabuf * eap_fast_process_pac(struct eap_sm *sm,
                                            struct eap_fast_data *data,
                                            struct eap_method_ret *ret,
                                            u8 *pac, size_t pac_len)
{
        struct eap_peer_config *config = eap_get_config(sm);
        struct eap_fast_pac entry;

        os_memset(&entry, 0, sizeof(entry));
        if (eap_fast_process_pac_tlv(&entry, pac, pac_len) ||
            eap_fast_process_pac_info(&entry))
                return NULL;

        eap_fast_add_pac(&data->pac, &data->current_pac, &entry);
        eap_fast_pac_list_truncate(data->pac, data->max_pac_list_len);
        if (data->use_pac_binary_format)
                eap_fast_save_pac_bin(sm, data->pac, config->pac_file);
        else
                eap_fast_save_pac(sm, data->pac, config->pac_file);

        if (data->provisioning) {
                if (data->anon_provisioning) {
                        /*
                         * Unauthenticated provisioning does not provide keying
                         * material and must end with an EAP-Failure.
                         * Authentication will be done separately after this.
                         */
                        data->success = 0;
                        ret->decision = DECISION_FAIL;
                } else {
                        /*
                         * Server may or may not allow authenticated
                         * provisioning also for key generation.
                         */
                        ret->decision = DECISION_COND_SUCC;
                }
                wpa_printf(MSG_DEBUG, "EAP-FAST: Send PAC-Acknowledgement TLV "
                           "- Provisioning completed successfully");
        } else {
                /*
                 * This is PAC refreshing, i.e., normal authentication that is
                 * expected to be completed with an EAP-Success.
                 */
                wpa_printf(MSG_DEBUG, "EAP-FAST: Send PAC-Acknowledgement TLV "
                           "- PAC refreshing completed successfully");
                ret->decision = DECISION_UNCOND_SUCC;
        }
        ret->methodState = METHOD_DONE;
        return eap_fast_tlv_pac_ack();
}


static int eap_fast_parse_decrypted(struct wpabuf *decrypted,
                                    struct eap_fast_tlv_parse *tlv,
                                    struct wpabuf **resp)
{
        int mandatory, tlv_type, len, res;
        u8 *pos, *end;

        os_memset(tlv, 0, sizeof(*tlv));

        /* Parse TLVs from the decrypted Phase 2 data */
        pos = wpabuf_mhead(decrypted);
        end = pos + wpabuf_len(decrypted);
        while (pos + 4 < end) {
                mandatory = pos[0] & 0x80;
                tlv_type = WPA_GET_BE16(pos) & 0x3fff;
                pos += 2;
                len = WPA_GET_BE16(pos);
                pos += 2;
                if (pos + len > end) {
                        wpa_printf(MSG_INFO, "EAP-FAST: TLV overflow");
                        return -1;
                }
                wpa_printf(MSG_DEBUG, "EAP-FAST: Received Phase 2: "
                           "TLV type %d length %d%s",
                           tlv_type, len, mandatory ? " (mandatory)" : "");

                res = eap_fast_parse_tlv(tlv, tlv_type, pos, len);
                if (res == -2)
                        break;
                if (res < 0) {
                        if (mandatory) {
                                wpa_printf(MSG_DEBUG, "EAP-FAST: Nak unknown "
                                           "mandatory TLV type %d", tlv_type);
                                *resp = eap_fast_tlv_nak(0, tlv_type);
                                break;
                        } else {
                                wpa_printf(MSG_DEBUG, "EAP-FAST: ignored "
                                           "unknown optional TLV type %d",
                                           tlv_type);
                        }
                }

                pos += len;
        }

        return 0;
}


static int eap_fast_encrypt_response(struct eap_sm *sm,
                                     struct eap_fast_data *data,
                                     struct wpabuf *resp,
                                     u8 identifier, struct wpabuf **out_data)
{
        if (resp == NULL)
                return 0;

        wpa_hexdump_buf(MSG_DEBUG, "EAP-FAST: Encrypting Phase 2 data",
                        resp);
        if (eap_peer_tls_encrypt(sm, &data->ssl, EAP_TYPE_FAST,
                                 data->fast_version, identifier,
                                 resp, out_data)) {
                wpa_printf(MSG_INFO, "EAP-FAST: Failed to encrypt a Phase 2 "
                           "frame");
        }
        wpabuf_free(resp);

        return 0;
}


static struct wpabuf * eap_fast_pac_request(void)
{
        struct wpabuf *tmp;
        u8 *pos, *pos2;

        tmp = wpabuf_alloc(sizeof(struct eap_tlv_hdr) +
                           sizeof(struct eap_tlv_request_action_tlv) +
                           sizeof(struct eap_tlv_pac_type_tlv));
        if (tmp == NULL)
                return NULL;

        pos = wpabuf_put(tmp, 0);
        pos2 = eap_fast_write_pac_request(pos, PAC_TYPE_TUNNEL_PAC);
        wpabuf_put(tmp, pos2 - pos);
        return tmp;
}


static int eap_fast_process_decrypted(struct eap_sm *sm,
                                      struct eap_fast_data *data,
                                      struct eap_method_ret *ret,
                                      const struct eap_hdr *req,
                                      struct wpabuf *decrypted,
                                      struct wpabuf **out_data)
{
        struct wpabuf *resp = NULL, *tmp;
        struct eap_fast_tlv_parse tlv;
        int failed = 0;

        if (eap_fast_parse_decrypted(decrypted, &tlv, &resp) < 0)
                return 0;
        if (resp)
                return eap_fast_encrypt_response(sm, data, resp,
                                                 req->identifier, out_data);

        if (tlv.result == EAP_TLV_RESULT_FAILURE) {
                resp = eap_fast_tlv_result(EAP_TLV_RESULT_FAILURE, 0);
                return eap_fast_encrypt_response(sm, data, resp,
                                                 req->identifier, out_data);
        }

        if (tlv.iresult == EAP_TLV_RESULT_FAILURE) {
                resp = eap_fast_tlv_result(EAP_TLV_RESULT_FAILURE, 1);
                return eap_fast_encrypt_response(sm, data, resp,
                                                 req->identifier, out_data);
        }

        if (tlv.crypto_binding) {
                tmp = eap_fast_process_crypto_binding(sm, data, ret,
                                                      tlv.crypto_binding,
                                                      tlv.crypto_binding_len);
                if (tmp == NULL)
                        failed = 1;
                else
                        resp = wpabuf_concat(resp, tmp);
        }

        if (tlv.iresult == EAP_TLV_RESULT_SUCCESS) {
                tmp = eap_fast_tlv_result(failed ? EAP_TLV_RESULT_FAILURE :
                                          EAP_TLV_RESULT_SUCCESS, 1);
                resp = wpabuf_concat(resp, tmp);
        }

        if (tlv.eap_payload_tlv) {
                tmp = eap_fast_process_eap_payload_tlv(
                        sm, data, ret, req, tlv.eap_payload_tlv,
                        tlv.eap_payload_tlv_len);
                resp = wpabuf_concat(resp, tmp);
        }

        if (tlv.pac && tlv.result != EAP_TLV_RESULT_SUCCESS) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: PAC TLV without Result TLV "
                           "acknowledging success");
                failed = 1;
        } else if (tlv.pac && tlv.result == EAP_TLV_RESULT_SUCCESS) {
                tmp = eap_fast_process_pac(sm, data, ret, tlv.pac,
                                           tlv.pac_len);
                resp = wpabuf_concat(resp, tmp);
        }

        if (data->current_pac == NULL && data->provisioning &&
            !data->anon_provisioning && !tlv.pac &&
            (tlv.iresult == EAP_TLV_RESULT_SUCCESS ||
             tlv.result == EAP_TLV_RESULT_SUCCESS)) {
                /*
                 * Need to request Tunnel PAC when using authenticated
                 * provisioning.
                 */
                wpa_printf(MSG_DEBUG, "EAP-FAST: Request Tunnel PAC");
                tmp = eap_fast_pac_request();
                resp = wpabuf_concat(resp, tmp);
        }

        if (tlv.result == EAP_TLV_RESULT_SUCCESS && !failed) {
                tmp = eap_fast_tlv_result(EAP_TLV_RESULT_SUCCESS, 0);
                resp = wpabuf_concat(tmp, resp);
        } else if (failed) {
                tmp = eap_fast_tlv_result(EAP_TLV_RESULT_FAILURE, 0);
                resp = wpabuf_concat(tmp, resp);
        }

        if (resp && tlv.result == EAP_TLV_RESULT_SUCCESS && !failed &&
            tlv.crypto_binding && data->phase2_success) {
                if (data->anon_provisioning) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Unauthenticated "
                                   "provisioning completed successfully.");
                        ret->methodState = METHOD_DONE;
                        ret->decision = DECISION_FAIL;
                } else {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: Authentication "
                                   "completed successfully.");
                        if (data->provisioning)
                                ret->methodState = METHOD_MAY_CONT;
                        else
                                ret->methodState = METHOD_DONE;
                        ret->decision = DECISION_UNCOND_SUCC;
                }
        }

        if (resp == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: No recognized TLVs - send "
                           "empty response packet");
                resp = wpabuf_alloc(1);
        }

        return eap_fast_encrypt_response(sm, data, resp, req->identifier,
                                         out_data);
}


static int eap_fast_decrypt(struct eap_sm *sm, struct eap_fast_data *data,
                            struct eap_method_ret *ret,
                            const struct eap_hdr *req,
                            const struct wpabuf *in_data,
                            struct wpabuf **out_data)
{
        struct wpabuf *in_decrypted;
        int res;

        wpa_printf(MSG_DEBUG, "EAP-FAST: Received %lu bytes encrypted data for"
                   " Phase 2", (unsigned long) wpabuf_len(in_data));

        if (data->pending_phase2_req) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Pending Phase 2 request - "
                           "skip decryption and use old data");
                /* Clear TLS reassembly state. */
                eap_peer_tls_reset_input(&data->ssl);

                in_decrypted = data->pending_phase2_req;
                data->pending_phase2_req = NULL;
                goto continue_req;
        }

        if (wpabuf_len(in_data) == 0) {
                /* Received TLS ACK - requesting more fragments */
                return eap_peer_tls_encrypt(sm, &data->ssl, EAP_TYPE_FAST,
                                            data->fast_version,
                                            req->identifier, NULL, out_data);
        }

        res = eap_peer_tls_decrypt(sm, &data->ssl, in_data, &in_decrypted);
        if (res)
                return res;

continue_req:
        wpa_hexdump_buf(MSG_MSGDUMP, "EAP-FAST: Decrypted Phase 2 TLV(s)",
                        in_decrypted);

        if (wpabuf_len(in_decrypted) < 4) {
                wpa_printf(MSG_INFO, "EAP-FAST: Too short Phase 2 "
                           "TLV frame (len=%lu)",
                           (unsigned long) wpabuf_len(in_decrypted));
                wpabuf_free(in_decrypted);
                return -1;
        }

        res = eap_fast_process_decrypted(sm, data, ret, req,
                                         in_decrypted, out_data);

        wpabuf_free(in_decrypted);

        return res;
}


static const u8 * eap_fast_get_a_id(const u8 *buf, size_t len, size_t *id_len)
{
        const u8 *a_id;
        struct pac_tlv_hdr *hdr;

        /*
         * Parse authority identity (A-ID) from the EAP-FAST/Start. This
         * supports both raw A-ID and one inside an A-ID TLV.
         */
        a_id = buf;
        *id_len = len;
        if (len > sizeof(*hdr)) {
                int tlen;
                hdr = (struct pac_tlv_hdr *) buf;
                tlen = be_to_host16(hdr->len);
                if (be_to_host16(hdr->type) == PAC_TYPE_A_ID &&
                    sizeof(*hdr) + tlen <= len) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: A-ID was in TLV "
                                   "(Start)");
                        a_id = (u8 *) (hdr + 1);
                        *id_len = tlen;
                }
        }
        wpa_hexdump_ascii(MSG_DEBUG, "EAP-FAST: A-ID", a_id, *id_len);

        return a_id;
}


static void eap_fast_select_pac(struct eap_fast_data *data,
                                const u8 *a_id, size_t a_id_len)
{
        data->current_pac = eap_fast_get_pac(data->pac, a_id, a_id_len,
                                             PAC_TYPE_TUNNEL_PAC);
        if (data->current_pac == NULL) {
                /*
                 * Tunnel PAC was not available for this A-ID. Try to use
                 * Machine Authentication PAC, if one is available.
                 */
                data->current_pac = eap_fast_get_pac(
                        data->pac, a_id, a_id_len,
                        PAC_TYPE_MACHINE_AUTHENTICATION);
        }

        if (data->current_pac) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: PAC found for this A-ID "
                           "(PAC-Type %d)", data->current_pac->pac_type);
                wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-FAST: A-ID-Info",
                                  data->current_pac->a_id_info,
                                  data->current_pac->a_id_info_len);
        }
}


static int eap_fast_use_pac_opaque(struct eap_sm *sm,
                                   struct eap_fast_data *data,
                                   struct eap_fast_pac *pac)
{
        u8 *tlv;
        size_t tlv_len, olen;
        struct eap_tlv_hdr *ehdr;

        olen = pac->pac_opaque_len;
        tlv_len = sizeof(*ehdr) + olen;
        tlv = os_malloc(tlv_len);
        if (tlv) {
                ehdr = (struct eap_tlv_hdr *) tlv;
                ehdr->tlv_type = host_to_be16(PAC_TYPE_PAC_OPAQUE);
                ehdr->length = host_to_be16(olen);
                os_memcpy(ehdr + 1, pac->pac_opaque, olen);
        }
        if (tlv == NULL ||
            tls_connection_client_hello_ext(sm->ssl_ctx, data->ssl.conn,
                                            TLS_EXT_PAC_OPAQUE,
                                            tlv, tlv_len) < 0) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to add PAC-Opaque TLS "
                           "extension");
                os_free(tlv);
                return -1;
        }
        os_free(tlv);

        return 0;
}


static int eap_fast_clear_pac_opaque_ext(struct eap_sm *sm,
                                         struct eap_fast_data *data)
{
        if (tls_connection_client_hello_ext(sm->ssl_ctx, data->ssl.conn,
                                            TLS_EXT_PAC_OPAQUE, NULL, 0) < 0) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to remove PAC-Opaque "
                           "TLS extension");
                return -1;
        }
        return 0;
}


static int eap_fast_set_provisioning_ciphers(struct eap_sm *sm,
                                             struct eap_fast_data *data)
{
        u8 ciphers[5];
        int count = 0;

        if (data->provisioning_allowed & EAP_FAST_PROV_UNAUTH) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Enabling unauthenticated "
                           "provisioning TLS cipher suites");
                ciphers[count++] = TLS_CIPHER_ANON_DH_AES128_SHA;
        }

        if (data->provisioning_allowed & EAP_FAST_PROV_AUTH) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Enabling authenticated "
                           "provisioning TLS cipher suites");
                ciphers[count++] = TLS_CIPHER_RSA_DHE_AES128_SHA;
                ciphers[count++] = TLS_CIPHER_AES128_SHA;
                ciphers[count++] = TLS_CIPHER_RC4_SHA;
        }

        ciphers[count++] = TLS_CIPHER_NONE;

        if (tls_connection_set_cipher_list(sm->ssl_ctx, data->ssl.conn,
                                           ciphers)) {
                wpa_printf(MSG_INFO, "EAP-FAST: Could not configure TLS "
                           "cipher suites for provisioning");
                return -1;
        }

        return 0;
}


static int eap_fast_process_start(struct eap_sm *sm,
                                  struct eap_fast_data *data, u8 flags,
                                  const u8 *pos, size_t left)
{
        const u8 *a_id;
        size_t a_id_len;

        /* EAP-FAST Version negotiation (section 3.1) */
        wpa_printf(MSG_DEBUG, "EAP-FAST: Start (server ver=%d, own ver=%d)",
                   flags & EAP_PEAP_VERSION_MASK, data->fast_version);
        if ((flags & EAP_PEAP_VERSION_MASK) < data->fast_version)
                data->fast_version = flags & EAP_PEAP_VERSION_MASK;
        wpa_printf(MSG_DEBUG, "EAP-FAST: Using FAST version %d",
                   data->fast_version);

        a_id = eap_fast_get_a_id(pos, left, &a_id_len);
        eap_fast_select_pac(data, a_id, a_id_len);

        if (data->resuming && data->current_pac) {
                wpa_printf(MSG_DEBUG, "EAP-FAST: Trying to resume session - "
                           "do not add PAC-Opaque to TLS ClientHello");
                if (eap_fast_clear_pac_opaque_ext(sm, data) < 0)
                        return -1;
        } else if (data->current_pac) {
                /*
                 * PAC found for the A-ID and we are not resuming an old
                 * session, so add PAC-Opaque extension to ClientHello.
                 */
                if (eap_fast_use_pac_opaque(sm, data, data->current_pac) < 0)
                        return -1;
        } else {
                /* No PAC found, so we must provision one. */
                if (!data->provisioning_allowed) {
                        wpa_printf(MSG_DEBUG, "EAP-FAST: No PAC found and "
                                   "provisioning disabled");
                        return -1;
                }
                wpa_printf(MSG_DEBUG, "EAP-FAST: No PAC found - "
                           "starting provisioning");
                if (eap_fast_set_provisioning_ciphers(sm, data) < 0 ||
                    eap_fast_clear_pac_opaque_ext(sm, data) < 0)
                        return -1;
                data->provisioning = 1;
        }

        return 0;
}


static struct wpabuf * eap_fast_process(struct eap_sm *sm, void *priv,
                                        struct eap_method_ret *ret,
                                        const struct wpabuf *reqData)
{
        const struct eap_hdr *req;
        size_t left;
        int res;
        u8 flags, id;
        struct wpabuf *resp;
        const u8 *pos;
        struct eap_fast_data *data = priv;

        pos = eap_peer_tls_process_init(sm, &data->ssl, EAP_TYPE_FAST, ret,
                                        reqData, &left, &flags);
        if (pos == NULL)
                return NULL;

        req = wpabuf_head(reqData);
        id = req->identifier;

        if (flags & EAP_TLS_FLAGS_START) {
                if (eap_fast_process_start(sm, data, flags, pos, left) < 0)
                        return NULL;

                left = 0; /* A-ID is not used in further packet processing */
        }

        resp = NULL;
        if (tls_connection_established(sm->ssl_ctx, data->ssl.conn) &&
            !data->resuming) {
                /* Process tunneled (encrypted) phase 2 data. */
                struct wpabuf msg;
                wpabuf_set(&msg, pos, left);
                res = eap_fast_decrypt(sm, data, ret, req, &msg, &resp);
                if (res < 0) {
                        ret->methodState = METHOD_DONE;
                        ret->decision = DECISION_FAIL;
                        /*
                         * Ack possible Alert that may have caused failure in
                         * decryption.
                         */
                        res = 1;
                }
        } else {
                /* Continue processing TLS handshake (phase 1). */
                res = eap_peer_tls_process_helper(sm, &data->ssl,
                                                  EAP_TYPE_FAST,
                                                  data->fast_version, id, pos,
                                                  left, &resp);

                if (tls_connection_established(sm->ssl_ctx, data->ssl.conn)) {
                        char cipher[80];
                        wpa_printf(MSG_DEBUG,
                                   "EAP-FAST: TLS done, proceed to Phase 2");
                        if (data->provisioning &&
                            (!(data->provisioning_allowed &
                               EAP_FAST_PROV_AUTH) ||
                             tls_get_cipher(sm->ssl_ctx, data->ssl.conn,
                                            cipher, sizeof(cipher)) < 0 ||
                             os_strstr(cipher, "ADH-") ||
                             os_strstr(cipher, "anon"))) {
                                wpa_printf(MSG_DEBUG, "EAP-FAST: Using "
                                           "anonymous (unauthenticated) "
                                           "provisioning");
                                data->anon_provisioning = 1;
                        } else
                                data->anon_provisioning = 0;
                        data->resuming = 0;
                        eap_fast_derive_keys(sm, data);
                }

                if (res == 2) {
                        struct wpabuf msg;
                        /*
                         * Application data included in the handshake message.
                         */
                        wpabuf_free(data->pending_phase2_req);
                        data->pending_phase2_req = resp;
                        resp = NULL;
                        wpabuf_set(&msg, pos, left);
                        res = eap_fast_decrypt(sm, data, ret, req, &msg,
                                               &resp);
                }
        }

        if (res == 1) {
                wpabuf_free(resp);
                return eap_peer_tls_build_ack(id, EAP_TYPE_FAST,
                                              data->fast_version);
        }

        return resp;
}


#if 0 /* FIX */
static Boolean eap_fast_has_reauth_data(struct eap_sm *sm, void *priv)
{
        struct eap_fast_data *data = priv;
        return tls_connection_established(sm->ssl_ctx, data->ssl.conn);
}


static void eap_fast_deinit_for_reauth(struct eap_sm *sm, void *priv)
{
        struct eap_fast_data *data = priv;
        os_free(data->key_block_p);
        data->key_block_p = NULL;
        wpabuf_free(data->pending_phase2_req);
        data->pending_phase2_req = NULL;
}


static void * eap_fast_init_for_reauth(struct eap_sm *sm, void *priv)
{
        struct eap_fast_data *data = priv;
        if (eap_peer_tls_reauth_init(sm, &data->ssl)) {
                os_free(data);
                return NULL;
        }
        if (data->phase2_priv && data->phase2_method &&
            data->phase2_method->init_for_reauth)
                data->phase2_method->init_for_reauth(sm, data->phase2_priv);
        data->phase2_success = 0;
        data->resuming = 1;
        data->provisioning = 0;
        data->anon_provisioning = 0;
        data->simck_idx = 0;
        return priv;
}
#endif


static int eap_fast_get_status(struct eap_sm *sm, void *priv, char *buf,
                               size_t buflen, int verbose)
{
        struct eap_fast_data *data = priv;
        int len, ret;

        len = eap_peer_tls_status(sm, &data->ssl, buf, buflen, verbose);
        if (data->phase2_method) {
                ret = os_snprintf(buf + len, buflen - len,
                                  "EAP-FAST Phase2 method=%s\n",
                                  data->phase2_method->name);
                if (ret < 0 || (size_t) ret >= buflen - len)
                        return len;
                len += ret;
        }
        return len;
}


static Boolean eap_fast_isKeyAvailable(struct eap_sm *sm, void *priv)
{
        struct eap_fast_data *data = priv;
        return data->success;
}


static u8 * eap_fast_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
        struct eap_fast_data *data = priv;
        u8 *key;

        if (!data->success)
                return NULL;

        key = os_malloc(EAP_FAST_KEY_LEN);
        if (key == NULL)
                return NULL;

        *len = EAP_FAST_KEY_LEN;
        os_memcpy(key, data->key_data, EAP_FAST_KEY_LEN);

        return key;
}


static u8 * eap_fast_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
{
        struct eap_fast_data *data = priv;
        u8 *key;

        if (!data->success)
                return NULL;

        key = os_malloc(EAP_EMSK_LEN);
        if (key == NULL)
                return NULL;

        *len = EAP_EMSK_LEN;
        os_memcpy(key, data->emsk, EAP_EMSK_LEN);

        return key;
}


int eap_peer_fast_register(void)
{
        struct eap_method *eap;
        int ret;

        eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
                                    EAP_VENDOR_IETF, EAP_TYPE_FAST, "FAST");
        if (eap == NULL)
                return -1;

        eap->init = eap_fast_init;
        eap->deinit = eap_fast_deinit;
        eap->process = eap_fast_process;
        eap->isKeyAvailable = eap_fast_isKeyAvailable;
        eap->getKey = eap_fast_getKey;
        eap->get_status = eap_fast_get_status;
#if 0
        eap->has_reauth_data = eap_fast_has_reauth_data;
        eap->deinit_for_reauth = eap_fast_deinit_for_reauth;
        eap->init_for_reauth = eap_fast_init_for_reauth;
#endif
        eap->get_emsk = eap_fast_get_emsk;

        ret = eap_peer_method_register(eap);
        if (ret)
                eap_peer_method_free(eap);
        return ret;
}
